Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Electrochemical potentiometric sensors measure concentrations of an analyte by measuring voltage differences that develop between two or more electrodes exposed to a solution containing one or more analytes. One of the two more electrodes is a reference electrode that has a known potential in the solution that is substantially unchanged by changes in concentration of the one or more analytes. Another of the two or more electrodes is a working electrode whose potential in the solution is selectively changed by changes in concentration of the one or more analytes. Substantially no current is allowed to flow through the reference and working electrodes. The voltage difference between the reference electrode and the working electrode is thus related to the concentration of the one or more analytes in the solution. Measurement of the voltage between the reference electrode and the working electrode can be performed by a high-impedance voltmeter.